Qualitative mapping of Barrett's metaplasia: a prerequisite for intervention trials

Background: Barrett's esophagus may present as a cellular mosaic with irreg ular longitudinal extensions of intestinal epithelium, spotty areas of dysp lasia and other Intermediate markers for cancer risk. It may not be possibl e to detect and reproducibly localize these findings with routine endoscopi c biopsies. A more systematic biopsy protocol is necessary for chemoprevent ive studies to be feasible. Methods: Utilizing an adapted upper endoscope that allows accurate evaluati on of distance from the incisors and rotatory position, chromoendoscopy wit h toluidine blue and systematic mapping (4 quadrant jumbo biopsies at 1 cm intervals) were performed twice on 18 patients with Barrett's esophagus (se cond procedure 1 to 3 months after baseline study). All biopsy specimens we re subjected to routine and immunohistochemical staining and flow cytometry to create baseline and follow-up maps for each patient. Eight of the 18 pa tients also underwent standard surveillance biopsies within 6 months of the systematic mapping procedures. Results: Epithelium type was reproducibly identified with 94% accuracy on s econd endoscopic maps. Ploidy, p53, and Ki-67 status were also reproducibly identified on second endoscopic maps (97%, 89%, and 85%, respectively). Dy splasia was found in 7 of 18 patients at similar sites at each mapping proc edure (3 patients with high-grade dysplasia, 4 with low-grade dysplasia). F ive of the patients who had dysplasia on mapping had also undergone standar d surveillance. Low-grade dysplasia was missed in 2 of 3 patients and 1 pat ient with high-grade dysplasia had only low-grade dysplasia detected with s tandard biopsies. Conclusions: Utilizing a modified gastroscope and this methodology, we reli ably located sites of dysplasia and other biomarkers within a field of Barr ett's esophagus. patients had variable areas of dysplasia that were missed on standard endoscopic surveillance.